Ammar-Khodja, FaridBenabdallah, AssiaGonzález Burgos, ManuelTeresa de Oteyza, María de la Luz de2016-09-282016-09-282014-10-01Ammar-Khodja, F., Benabdallah, A., González Burgos, M. y Teresa de Oteyza, M.d.l.L.d. (2014). Minimal time for the null controllability of parabolic systems: the effect of the condensation index of complex sequences. Journal of Functional Analysis, 267 (1), 2077-2151.0022-1236http://hdl.handle.net/11441/46189Let (A, D(A)) a diagonalizable generator of a C0−semigroup of contractions on a complex Hilbert space X, B2L(C, Y ), Y being some suitable extrapolation space of X, and u 2 L2 (0, T; C). Under some assumptions on the sequence of eigenvalues Λ = {λk}k≥1 ⇢ C of (A, D(A)), we prove the existence of a minimal time T0 2 [0, 1] depending on Bernstein’s condensation index of Λ and on B such that y 0 = Ay+Bu is null-controllable at any time T >T0 and not null-controllable for T <T0. As a consequence, we solve controllability problems of various systems of coupled parabolic equations. In particular, new results on the boundary controllability of one-dimensional parabolic systems are derived. These seem to be difficult to achieve using other classical tools.application/pdfengAttribution-NonCommercial-NoDerivatives 4.0 Internacionalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Null controllabilityParabolic systemsMinimal timeCondensation index of complex sequencesinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccesshttps://doi.org/10.1016/j.jfa.2014.07.024